Grant Expansion Vessel 12Ltr G Cs23 " Bsp C/W Hose 125 - 150

Grant Expansion Vessel 12Ltr G Cs23 " Bsp C/W Hose 125 - 150

Grant Expansion Vessel 12 Litre – GCS23

Part Number: GCS23
Compatible with Grant Cylinders 125–150L | Includes Hose | ½” BSP Connection

Ensure your Grant hot water system remains safe and efficient with the Grant 12L Expansion Vessel – GCS23, complete with a ½" BSP connection and pre-fitted hose. Specially designed for Grant cylinders ranging from 125L to 150L, this sealed system component helps maintain stable pressure by absorbing water expansion during heating, preventing unnecessary pressure relief valve activation.

Ideal for new installations or as a direct replacement in existing setups, this expansion vessel provides reliable performance, long service life, and compliance with unvented cylinder safety regulations.

Key Features

• 12-litre capacity – suitable for 125–150 litre Grant cylinders

• ½" BSP male connection – standard for domestic systems

• Supplied complete with flexible connecting hose

• Helps prevent over-pressurisation in sealed hot water systems

• Reliable diaphragm design for long-term durability

• Pre-charged and easy to install

• Reduces stress on components like PRVs and joints

• OEM Grant part for guaranteed compatibility and quality

Compatible Models

This expansion vessel is suitable for use with:

• Grant Unvented Cylinders – 125L & 150L capacity

• All Grant hot water systems requiring a 12L vessel

• Any sealed system requiring a pressure expansion unit with ½" BSP

When to Replace the Expansion Vessel

• If pressure fluctuates rapidly or PRVs discharge regularly

• During routine cylinder servicing or pressure loss diagnosis

• If the diaphragm fails (evident by water exiting the Schrader valve)

• When signs of internal corrosion or visible damage appear

• After 5–8 years of use or as advised by manufacturer/service engineers

Technical Specifications

• Part Number: GCS23

• Capacity: 12 Litres

• Connection: ½” BSP (British Standard Pipe)

• Supplied with: Pre-attached flexible hose

• Compatible Cylinder Sizes: 125L – 150L

• Mounting Position: Vertical wall-mountable or floor-standing

• System Type: Sealed/unvented hot water systems

• Pre-Charge Pressure: Typically 1.5 bar (check manufacturer guidelines)